Method and apparatus for determination of surface properties of coatings by determining contrast of an evaluated image

Abstract

A method is provided for the quantitative determination of surface properties, wherein a spatially resolved image of a surface to be analyzed, which contains a large number of measured values, is recorded. In a first method step, the measured values are analyzed in order to determine those surface areas which have a specific physical property. A result value of this physical property is then determined, wherein this result value is characteristic of the values of the physical property of all those surface areas of the image determined by analyzing the image. In addition to the result value, a further value (B) characteristic of the surface is determined and this characteristic value is displayed together with the result value (I).

The invention claimed is: 
     
       1. A method for the quantitative determination of surface properties of coatings containing effect pigments, said method comprising the steps:
 recording at least one spatially resolved image of an entire surface to be analysed by a camera or a detection device; 
 assigning, by a processor device, at least one measured value to each of the pixels of the image, wherein said measured value corresponds to a given specific colour property; analysing the measured values by:
 determining those surface areas (A) of the at least one recorded image which represent each said specific colour property; 
 determining a mean value (I) of said specific colour property with the processor device, wherein said mean value is characteristic of the measured values of the colour property of all said determined surface areas (A), 
 
 evaluating individual camera pixels or pixels of the detection device with the processor device according to a specified defined value range for an intensity of one or more colours in the at least one recorded image by:
 once again determining certain surface areas of the at least one recorded image, which represent a specific colour property; 
 determining a further characteristic value (B), which is independent of the mean value (I), wherein the further characteristic value represents colour properties of the at least one recorded image which lie above a given threshold value and wherein its determination is based on the determined surface areas; and 
 
 displaying said further characteristic value (B) together with the mean value (I) or a value dependent on this mean value. 
 
     
     
       2. The method according to  claim 1 , comprising:
 emitting radiation onto the surface to be analysed, and receiving at least a proportion of the radiation, reflected from the surface to be analysed, by a radiation detector device and outputting the measured values or data characteristic of these measured values by this radiation detector device. 
 
     
     
       3. The method according to  claim 1 , comprising:
 determining a size of the determined surface areas (A) by determining a number of pixels corresponding to the determined surface areas (A) and identifying the size of the determined surface areas (A) with this number; and 
 determining the further characteristic value (B) by identifying it with the size of the determined surface areas (A); and 
 outputting/displaying the mean value (I) against the size of the determined surface areas (A) wherein the size is determined from a number of pixels corresponding to the surface areas. 
 
     
     
       4. The method according to  claim 1 , comprising:
 determining the mean value (I) by taking a mean from a group of means comprising arithmetic means, geometric means, integrals, weighted means, combinations thereof. 
 
     
     
       5. The method according to  claim 1 , wherein the colour property is a colour intensity. 
     
     
       6. The method according to  claim 1 , comprising:
 determining the size of those surface areas which characterises a specific value range of said characteristic value (B). 
 
     
     
       7. A method for the quantitative determination of surface properties of coating containing effect pigments comparing more than one spatially resolved image, comprising the steps:
 (I) recording at least one spatially resolved image of an entire surface to be analysed by a camera or a detection device; 
 (II) assigning, by a processor device, at least one measured value to each of the pixels of the image, wherein said measured value corresponds to a given specific colour property; 
 (III) analysing the measured values by: 
 (a) determining those surface areas (A) of the at least one recorded image which represent each said specific colour property; 
 (b) determining a mean value (I) of said specific colour property with the processor device, wherein said mean value is characteristic of the measured values of the colour property of all said determined surface areas (A), 
 evaluating individual camera pixels or pixels of the detection device with the processor device according to a specified defined value range for an intensity of one or more colours in the at least one recorded image by: 
 (c) once again determining certain surface areas of the at least one recorded image, which represent a specific colour property; and 
 (d) determining a further characteristic value (B), which is independent of the mean value (I), wherein the further characteristic value represents colour properties of the at least one recorded image which lie above a given threshold value and wherein its determination is based on the determined surface areas; and 
 repeating steps (I)-(III) for each spatially resolved image, each time ending up with a mean value (I) and a characteristic value (B), and 
 plotting said characteristic values (B) together with the mean value (I) for more than one spatially resolved image. 
 
     
     
       8. The method according to  claim 1 , comprising:
 defining a tolerance region, which determines whether a predefined mean value (I) and said characteristic value (B) meet previously set tolerance criteria, 
 and displaying the tolerance region together with the mean value (I) and the characteristic value (B). 
 
     
     
       9. The method according to  claim 5 , further comprising determining the surface areas (A) of the recorded image according to having a scattering intensity above a given threshold value. 
     
     
       10. The method according to  claim 1 , comprising:
 defining a tolerance region, which determines whether predefined mean values and characteristic values meet previously set tolerance criteria, wherein said tolerance region is determined both with regard to the mean values and with regard to the characteristic values; 
 defining a tolerance zone, which determines whether certain predefined sub-areas of the coating to be investigated meet these previously set tolerance criteria, wherein the tolerance zone services for the assessment of whether certain regions of the coating to be investigated can or cannot be tolerated; 
 displaying said further characteristic value (B) together with the mean value (I) or a value dependent on this mean value in a diagram, in which a tolerance region and a tolerance zone are displayed. 
 
     
     
       11. A method for the quantitative determination of surface properties of coatings containing effect pigments, said method comprising the steps:
 recording at least one spatially resolved image of the entire surface to be analysed by a camera or a detection device; 
 assigning, by a processor device, at least one measured value to each of the pixels of the image, wherein said measured value corresponds to a given specific colour property; 
 analyzing the measured values by:
 determining those surface areas (A) of the at least one recorded image which represent each a given specific colour property; 
 determining a mean value (I) of said specific colour property with the processor device, wherein said mean value is characteristic of the measured values of the colour property of all said determined surface areas (A); 
 
 evaluating individual camera pixels or pixels of the detection device with the processor device according to a specific defined value range for an intensity of one or more colours in the at least one recorded image by:
 once again determining certain surface areas of the at least one recorded image, which represents a specific colour property; 
 determining a further characteristic value (B), which is independent of the mean value (I), wherein the further characteristic value (B) represents colour properties of the at least one recorded image which lie above a given threshold value and wherein its determination is based on the determined surface areas; and 
 
 displaying said further characteristic value (B) together with the mean value (I) or a value dependent on this mean value, wherein the mean value (I) is output against a size of the determined surface areas (A), wherein the size is determined from a number of pixels corresponding to the surface areas.